Enamel matrix proteins such as those present in enamel matrix are well-known as precursors of dental enamel. Enamel matrix proteins and enamel matrix derivatives have previously been described in the literature to induce enamel formation (U.S. Pat. No. 4,672,032, Slavkin) or binding between different types of mineralised tissue such as cementum and bone (EP-B0 337 967 and EP-B-0 263 086). Furthermore, enamel matrix proteins and derivatives have been disclosed to promote wound healing in soft tissues such as skin and mucosa (WO 99/43344). The use of enamel matrix proteins or enamel matrix derivatives for dentin regeneration has not, to the inventors' knowledge, been reported previously.
Exposure of vital dental pulp is a common complication, either accidentally or by design, during normal dental restorative and prosthodontic procedures and also following crown fractures, trauma, and caries. Traditionally minimal exposures of dental pulp are treated either by applying a Ca(OH)2 paste or a filling material (e.g. composites) directly onto the pulp to induce superficial necrosis sometimes followed by sclerotisation and reactive dentin formation deeper down in the pulp tissue. This strategy, however, seldom restores a mineralised barrier between the pulp and the restorative material(s) and in frequent cases the dental pulp becomes inflamed and has to be treated by pulpectomy (removal of the entire pulp) or pulpotomy (removal of a large portion of the pulp) and subsequent endodontic filling with synthetic materials (e.g. guttapercha). In the cases where a larger part of the pulp is exposed treatment always includes a pulpectomy and endodontic filling.
Endodontically treated teeth lose their blood supply, innervation and ability to produce reactive hard tissue (secondary dentin). As a result, these teeth become brittle and are also more prone to masticatory induced trauma and grave caries (due to lack of sensibility patients do not feel pain). This makes the lifespan of endodontically treated teeth much shorter than that of vital teeth and thus less useful as pillars for prosthodontic tooth replacements.
If a way to induce new dentin formation that efficiently can cover and seal off exposed dental pulp could be found, it would constitute a major breakthrough in conservative dentistry.